Directory look-aside table for a virtual data storage system.

摘要

The present invention relates to a directory look-aside table (65) for a virtual data storage system which can have pages in different address spaces having the same virtual addresses, the addresses (60) being identified by respective segment tables. According to the invention the table is characterised in that it comprises first means (61) for distinguishing between address spaces and data spaces, second means (62) for sub-classifying data spaces by one or more space identification discriminating low order bits, and third means (63, 64) responsive to said first and second means for providing a unique algorithm for each sub-class of data spaces for the assignment of virtual page address to directory look-aside table rows using virtual page-address bits. <IMAGE>